The "Bazooka" became a critical Allied weapon of World War 2 (1939-1945), charged with destruction of enemy armor and fortifications at range. At its core, it was a shoulder-fired, recoilless all-in-one weapon system capable of being carried by a sole infantryman into battle. So effective was the concept that the Germans, having reverse-engineered the type, issued a new 88mm anti-tank terror weapon to their own troops under the name of "Panzerschreck".
The Bazooka was introduced into service with the U.S. Army in November of 1942 and its first actions encompassed "Operation Torch", the Allied invasion of North Africa. In its earliest form, the weapon had an overall length of 54 inches and weighed 18lb unloaded. Its M6 HEAT (High-Explosive, Anti-Tank) projectile could penetrate up to 3 inches (76mm) of armor. With the arrival of the M1A1 production model in July of 1943, the series improved the electrical system and featured a simplified overall design. Weight was reduced to 13.25lb.
After this arrived the M9 model which began production in October. This form, continuing use of the 66mm rocket projectile, introduced a magneto-based trigger ignition system and could now be broken down into two more manageable sections for transport. The wooden furniture was also reworked to metal to ease production and lower costs. The improved M6A3 HEAT round was also introduced as we White Phosphorous and the M7A3 practice rocket. Penetration of the rocket munition now reached 4" (102mm) of armor protection. Overall length increased to 61 inches and weight increased to 15.15 inches as a result of the changes.
The overall Bazooka form remained with its general shape being a slim tube. A pistol grip / trigger unit was set at the midway point of the design and both ends of the tube were open - one to release the rocket munition (front) and the other to exhaust the propellant gasses (rear). A crude wire shoulder support was affixed to the aft section of the launch tube. Optimally, two personnel were used in the operation of the weapon - one to load / reload and the other to sight and fire. The two-piece nature of the weapon allowed a single infantryman to carry several M9 weapons if need be.
The M9A1 was a slightly improved version of the original M9 of June 1944 in that an improved coupling assembly was devised for the launch tube. An optical reflector sighting device, introduced in September of 1944, succeeded the old iron arrangement for improved accuracy at range. Overall length and weight remained largely the same.
The M18 was an experimental version of the M9A1 with aluminum alloy construction. While ordered before the end of the war in August-September of 1945, the design was cancelled with the conclusion of hostilities. This version was to have an overall unloaded weight of just 10.5lb.